Will the World’s Ecosystems Be Up to Feeding a Population Growing to 8-10 Billion in a Changing Climate? Bill Easterling The Pennsylvania State University

THE SET UP

World Grain Demand to 2030 (~80% of calories) % by 2030—could be +100% by 2050 when factoring in economic growth! Can we keep pace?

Fig. 1 Changes in the relative global production of crops and animals since 1961 (when relative production scaled to 1 in 1961). H C J Godfray et al. Science 2010;327: Published by AAAS Well, how have we done to this point? ~15% of increase from land expansion, rest from yield increases! Yields: what are the odds that past performance will hold into the future? +

Yield Gaps: What is vs. what is possible

Slowing of yield increases

4 Categories of Yield Trends Source: Ray et al, 2012 Globally, 24-39%-- depending on the crop-- of cropland experiencing yield stagnation or collapse.

Human and Ecological Drivers of Production Declines But, for the traditionally highest yield growth areas, the real concern may be that we are reaching maximum yield potential for the natural genome.

USDA, We Have A Problem! Five countries account for 55% of global total agricultural production!

How much water was used to produce your last Quarter Pounder?

Relative Water Scarcity, 2006

THE STING

Green = with adaptation Red = without adaptation ___= reference line for current yields Cereal Yield Response to Warming—Temperate vs. Tropical Regions Temperate yields (including U.S) tend to thrive until +2-3˚C Tropical yields tend to decline immediately Adaptation not nearly as effective in tropics as temperate regions CO 2 effects included

Some concluding thoughts Adaptation is not optional Not all forms of adaptation will reduce system vulnerability Re: Food—Adaptation may be outpaced by climate change soon in Tropics and eventually in the Mid- to High Latitudes –Means that mitigation is not optional! First steps should be to address the world water challenge!